Colloidal silicate dispersion, method for its preparation and its use

ABSTRACT

The present invention is directed to a colloidal aqueous silicate dispersion containing silica and alumina, the molar ratio between silica and alumina being 2-12, as well as to a method for its preparation. Said method is characterized by dissolving a particulate mineral material, such as a mineral wool or fiber product containing silica and alumina in a molar ratio of 2-12 in an aqueous solution, nucleating and stabilizing the so obtained solution, and optionally adjusting the dry matter content of the dispersion so obtained. The said dispersion can also be made to gel. The invention is also directed to the use of the dispersion as a binder.

FIELD OF THE INVENTION

[0001] The present invention relates to colloidal silicate dispersions,preferably having a low alkali content and containing in additionalumina, as well as to gels formed from such dispersions throughcoagulation or gel formation. The invention is also related to a methodfor the preparation of such dispersions, using silica and aluminacontaining particulate silicate mineral raw materials. In addition, theinvention is directed to the use of the dispersions so obtained,especially as a material with binding capacity, i.e. as a binding agent,or as a binding component in a binder composition, including the use asa coating substance or adhesive, or as a binding component in coatingand adhesive compositions. In particular the materials of the inventionfind use in construction materials, in particular as a binder in mineralwool production, or in cementitious or concrete products.

BACKGROUND OF THE INVENTION

[0002] Water glass is traditionally made by melting silica sand withsodium or potassium carbonate at a very high temperature and thendissolving the finely divided solidified product in water. Thus waterglass can be considered an ecologically acceptable substance to includein construction materials, such as a binder in mineral wool products orin cementitious products. Water glass has also been used as a binder inraw material briquettes for mineral wool production, or as binders formaking foundry molds or cores, or for use as coating substances andadhesives. Thus for example DE 28 04 069 refers to a method of producingan insulating product by binding mineral fibres with water glass.

[0003] One disadvantage relating to the use of water glass is, however,that its manufacture uses pure raw materials and is very energyconsuming. Another disadvantage is that such water glass is a highlyalkaline product, which can cause stability problems, for example whenused as a binder in cementituous products. Water glass typically has aRB ratio (the molar ratio SiO₂/Na₂O) of from appr. 1 to 4, the ratio ofcommercial water glass being typically appr. 3.3.

[0004] It is also known to use a mixture of water glass with othersubstances for various purposes, such as with clay or cement as a binderfor mineral wool products, see e.g. SE 420 488. Such a product, althoughproviding good water and heat resistance, has poor compressionresistance, is brittle and causes dusting. The EP B 466 754 on the otherhand describes the use of a binder made from slag activated with waterglass for making a temperature and moisture resistant mineral woolproduct which is also capable of withstanding high temporary loads.

[0005] EP 59 088 describes high alkali silicate solutions to be used forbinding purposes, especially for foundry moulds and cores, whichsolutions are made by dissolving finely divided silica powder into analkaline solution, the resultant solution having a Rs value of 1.6 to3.5. The silicate solutions so prepared have a low alumina content,typically below 2%.

SUMMARY OF THE INVENTION

[0006] In a first aspect, the present invention is directed to acolloidal aqueous silicate dispersion, i.e. a silicate containing sol,suitable for use as a binding agent, the dispersed binding componentbeing preferably based on a mineral material and having a content ofsilicium and aluminium, calculated as their respective oxides, in asuitable ratio, that is expressed as the molar ratio between silica andalumina, i.e. SiO₂/Al₂O₃, to provide a stable product for a variety ofuses. According to the invention, the ratio between the silica moles tothe alumina moles in the dispersion is in the range of 2-12, that is2:1-12:1. Preferably such a ratio is 2.5-8, and advantageously 3.5-6.

[0007] The present invention is also directed to a method for thepreparation of such dispersions, according to which method a particulatesilicate mineral material containing silica and alumina in a molar ratioof 2-12 is dissolved in an aqueous solution, to form a solutioncontaining nucleated re-precipitated particles from the material,stabilizing the solution to form a dispersion, and optionally adjustingthe dry matter content of the dispersion.

[0008] It is also within the scope of the invention to destabilize orcoagulate the dispersion to form a gel. Such gel formation can takeplace by various methods known in the art, such as by changing the pH ofthe dispersion, or adding an electrolyte, such as a salt, or by removingwater from the dispersion.

[0009] The present invention is also directed to the use of the silicatedispersion according to the invention. Such uses include the use as abinder for example in mineral wool production, or in the formation ofraw material briquettes for mineral wool production, or in metal orebriquettes, or as binders in foundry moulds and cores. It is alsopossible to use the dispersions as an additive to cement or in additionto cement for example in concrete products, where they, due to theincreased proportion of alumina, accelerate the binding process and actas strengtheners. Further uses include the use as coating materials inapplications where traditionally conventional water glass or silica solsor silica particles such as “aerosil” or fly ash have been used. Theyare especially suitable for the preparation of fire resistant coatings,which due to the high alumina content of the dispersion show improvedstability as compared to ordinary high alkali water glasses, the aluminaproviding for improved glassiness and reduced crystallinity of thesilicate binder. The dispersions according to the invention can also beused as a fire resistant adhesive, for example for wood, concrete,bricks, glass, metal, plywood, and plasterboard manufacture. Aparticular use is found in the glueing of laminates, for example whenlaminating mineral wool layers, or as an adhesive for gluing mineralwool, for example to a metal, such as a metal sheet, so as to formconstruction panels.

DETAILED DESCRIPTION OF THE INVENTION

[0010] According to the invention an improved and economically feasiblesilicate binder material has been provided, which has excellent binding,strengthening and fire resistant properties and is also acceptable froma use or labour hygiene point of view. In addition, the binder accordingto the invention can be manufactured from inexpensive and easilyavailable raw materials, or by-products, in a simple manner, allowingfor the tailor-making of or designing the composition of the dispersionto suit the desired purpose. An important advantage is that thedispersion according to the invention presents no ecological load on theenvironment, but contains only such components that are alreadyinherently present in nature.

[0011] According to a preferred embodiment of the invention, thedispersion according to the invention has, in contrast to traditionalwater glass, a low alkali content, that is, it has a low content ofalkali oxides, in particular sodium and potassium oxides. According to afurther advantageous embodiment, the dispersion according to inventioncontains earth alkali metal oxides, such as calcium and/or magnesiumoxides and/or iron oxide. Such an embodiment gives i.a. improved waterresistance due to the fact that the aqueous solubility of earth alkalimetals is inferior to that of the alkali metals.

[0012] The low alkalinity makes the dispersion usable in a number ofapplications where a low alkalinity is desired, for example as a binderin concrete.

[0013] According to an embodiment of the invention, the colloidaldispersion contains silica and alkali oxide in a molar ratio, that isthe ratio of the silica moles to the sum of the alkali oxide moles, i.e.essentially the sum of the sodium oxide moles and/or the potassium oxidemoles, which is in the range of 10-350, preferably 15-150. The desiredmolar ratio can be obtained by properly selecting the starting mineralraw material to be used for making the dispersion.

[0014] According to a further embodiment of the invention, thedispersion contains calcium and/or magnesium oxide and/or iron oxide,wherein the molar ratio between silica and the sum of calcium, magnesiumand iron oxide is in the range of 0.5-2, preferably 0.6-1.5. The ironoxide is calculated in the form of FeO.

[0015] According to a preferred embodiment, the primary particle size ofthe dispersion is 1 to 1000 nm, preferably 10 to 100 nm.

[0016] The dry matter content of the dispersion can vary, depending onthe intended application, but for most purposes a dry matter contentabove 1%, such as ranging between 5 and 60% by weight is suitable. Thedry matter content of the dispersion can be adjusted by removing water,for example by evaporation, or adding water in a suitable manner.

[0017] As is explained in more detail below, the dispersion according tothe invention can easily be transformed to a gel, for example usingphysico-chemical means, such as removing the electrostatic repulsionbetween the dispersion particles by changing pH or by adding anelectrolyte, or a surfactant. Gel formation can also be carried out bydrying the dispersion.

[0018] An object of the present invention is also a method for makingthe said dispersion comprising the steps of

[0019] dissolving a particulate mineral material containing silica andalumina in a molar ratio of 2-12 in an aqueous solution, to form asolution containing nucleated re-precipitated particles from thematerial,

[0020] stabilizing the so obtained solution to form a dispersion havinga desired particle size, and optionally

[0021] adjusting the dry matter content of the dispersion.

[0022] Preferably the particulate mineral material used as a startingmaterial is a material having a glassy amorphous structure. Such aglassy structure has better dissolution properties than a crystallinestructure, and are formed for example when mineral raw materials aremolten and formed into fibres at high temperature. A suitable rawmaterial is thus a mineral wool material or mineral fiber product, forexample a waste or by product from mineral fiber production, such asspinning waste, unused fibres or products, as well as post-consumermineral fiber products.

[0023] A mineral material suitable for use as a starting materialcontains SiO2 in an amount of 35-45% by weight and Al₂O₃ in an amount of8-25% by weight.

[0024] According to an advantageous embodiment a low alkali particulatemineral material contains, calculated as % by weight, SiO₂ 35-45 Al₂O₃10-25 R₂O 0.2-3, 

[0025] wherein R means Na or K. In addition, such a material cancontain, calculated as % by weight, CaO 12-35 MgO  6-20 FeO (total iron)  2-10.

[0026] A further suitable mineral material type is a material having thefollowing composition, calculated as % by weight SiO₂ 35-45 Al₂O₃  8-13R₂O 0.2-1, 

[0027] wherein R means Na or K. In addition, such a material cancontain, calculated as % by weight, CaO 30-40 MgO  5-11 FeO (total iron)0.1-1. 

[0028] This composition is a typical composition for example for a slagwool product. Thus an advantageous starting material for making thedispersion can be a product or by-product obtained from the manufactureof slag wool.

[0029] The inclusion of earth alkali metal oxides has the furtheradvantage of providing materials suitable for water resistant coatingsand binders. Such inclusion is of special importance for example whenused in briquettes, such as raw material briquettes for mineral woolproduction, or in ore briquettes, as well as for providing waterresistant and stable coatings and adhesives.

[0030] Preferably the starting material used for forming the dispersionis in the form of a mineral wool material, especially obtained as a sideor waste product from mineral wool production, as indicated above. Amaterial can then be chosen which has the optimal or desired compositionfor the preparation of the dispersions according to the invention. Suchwaste materials are formed in large quantities, typically in amounts upto 20-30% by weight of the starting raw material, in the form ofspinning waste, shots and unused fibers of rejected fibrous products(pre-consumer products). One applicable source for the material are alsodifferent constructions which are taken down and in which mineral woolmaterial has been used, for instance, as heat insulation (post-consumerproducts). Such a waste material is already in finely divided, typicallyfibrous form and can thus be used as such, or alternatively it can alsobe divided to an even finer form to provide a product with a largesurface area, such as 0.4 m²/g or larger, for example up to 25 m²/g, andthus has good dissolution properties in the aqueous solution. Fibresobtained from mineral wool production typically have a diameter of 0.5to 20, usually 2 to 15 μm, such as 3 to 5 μm as measured with OM or SEMusing a suitable method (e.g. Koenig et al, Analytica Chimica Acta 1993280 289-298; Christensen et al, AM IND HYG ASSOC (54) May 1993), and alength of 0.5 to 50 mm, usually 2 to 20 mm, such as 3 to 10 mm.

[0031] The aqueous solution is an acidic solution, such as an aqueoussolution made acidic by adding an inorganic or organic acid, such asHCl, HNO₃, H₂SO₄, H₃PO₄, formic, acetic, propionic acid or any othersuitable mineral or organic acid. The pH of the solution is adjustedsuitably. A low pH value results in a rapid dissolution of the mineralmaterial to form a gel, the gelling time being dependent on the pH alower pH resulting in a more rapid gelling than a higher pH. Gooddissolution for a wide range of mineral materials is obtained at a pH of0 to 6. The strength of the acid can be, depending on the acid used,from 0.1 to 10 M, such as 0.5 to 5 M.

[0032] The aqueous solution can also be an alkaline solution, such as analkali metal or earth alkali metal hydroxy, carbonate or hydrocarbonatesolution, especially a sodium, potassium or lithium hydroxide solution,or an ammonium hydroxide solution. Such a solution is preferably 0.1 to2 molar with respect to the alkaline agent, or has a pH of 10 to 14, inorder to easily dissolve also such mineral raw materials that are poorlysoluble in neutral solutions.

[0033] At an alkaline pH the dispersion tends to be stable and anincrease in particle size can be seen. By maintaining the dispersion atan alkaline pH for a suitable time, or by increasing the pH from appr.neutral to pH 10, an increase in particle size is obtained, the increasebeing less pronounced if the solution in addition contains salts. In thepresence of sufficient quantities of salts, such as inorganic salts,e.g. sodium chloride, the particles tend to aggregate to form gels,which precipitate. The same gel formation will also take place byproviding an acid pH to the solution, whereby a pH of appr. 2 to below 7is suitable for gel formation.

[0034] Thus by adjusting the pH the dispersion state can be maintained,or the dispersion can be made to gel. The gel can be dispersed andstabilized by using high-shear mixing and raising the pH, and then againbe brought to gelling by readjusting lowering) the pH, or by theaddition of an electrolyte.

[0035] Alumina containing particulate mineral materials, especially suchcontaining from appr. 10-25% by weight of alumina, are generallyrelatively poorly soluble in neutral solutions, but exhibit improveddissolution in acidic and alkaline media, thus providing aqueousdispersions containing dissolved silica and dissolved alumina in thedesired ratio. According to the invention, when dissolving the materialin an acidic solution, organic acids are preferred to inorganic acids.This is due to the fact that inorganic acids can form insoluble saltprecipitations, for example with calcium and magnesium included in thestarting material. Also some of the inorganic acids are highly corrosiveand thus not preferred for obvious reason.

[0036] According to a preferred embodiment, the dissolution of the rawmaterial is preferably carried out at an increased temperature, such asat a temperature of 80 to 100° C., preferably while simultaneouslystirring, in order to facilitate the dissolution process. Dissolutiontakes place within a period from 1-2 hours up to 20 hours depending onthe dissolving medium used and the solids content of the solution.Preferably an amount of starting mineral material is dissolved in thesolution to provide a metal oxide containing solution whichadvantageously contains over 1%, preferably 5 to 60% by weight of drymatter, which is a suitable concentration for the subsequent use as abinder. After the dissolution is complete, the material nucleates andre-precipitates to form a dispersion with the desired particle size. Thesubsequent stabilization of the dispersion is brought about by creating,in the solution, electrostatic repulsion between the particles. Theelectrostatic repulsion between the particles can be effected forexample by providing suitable ions in the solution, or by changing thepH of the solution. If necessary, additional water can be added orremoved, e.g. by evaporation, if necessary, for example for adjustingthe viscosity of the solution obtained.

[0037] Stabilization may also be achieved by using suitable surfactantsand/or polymers, especially non-ionic ones. Non-ionic surfactants andpolymers can be preferred in some cases as they are not very sensitiveto an environment which contains high concentrations of electrolytes andother chemicals, especially when the ionic strength is high. Examples ofsuitable polymers are polyethylene oxide and polyethylene glycol.Examples of suitable surfactants are nonylphenols, Tween and Span. In atypical situation, such surfactants and polymers are used in an amountof 0.5 to 2.5% by weight, calculated from the total solids of thesolution. As stated above, the particle size of the dispersion can beadjusted by adjusting the pH.

[0038] According to the invention it is thus possible to providedispersions containing predominantly silica in combination with othermetal oxides stemming from the starting mineral material, such ascalcium oxide, magnesium oxide, aluminium oxide, and possibly furthermetal oxides in smaller amounts. It is also possible to adjust thereaction conditions so as to obtain dispersions with a desired particlesize. The dispersions so obtained can be made to gel either directlyafter formation, or only immediately prior to application, for exampleprior to application of the dispersion as a binder onto mineral fibresin mineral wool production. The dispersion can also be made to gel whenheating or evaporating water when the final product is shaped.

[0039] The amount of dispersion to be used for any particular purposecan easily be determined by a person skilled in the art As an example itcan be mentioned that when used as a binder in mineral wool production,the amount of binder generally is appr. 1 to 15% by weight, calculatedas dry substance, of the weight of the product, for a normal insulatingproduct, but it is naturally possible to use higher and lower amountsdepending on the desired product and the reactivity of the binder. Whenused as a binder in foundry mould applications, a typical amount wouldbe appr. 1 to 15%, such as 1 to 5% by weight of the total weight of thebatch.

[0040] The following examples illustrate the invention, without limitingthe same. Percentages are in percent by weight unless otherwisespecified.

EXAMPLE 1

[0041] The binder according to the invention can be prepared in thefollowing way.

[0042] 7.5 g of mineral fibres containing 42.1% SiO₂, 17.4% Al₂O₃, 17.3%CaO 13.7% MgO, 5.8% FeO, 1.6% Na₂O, 0.6% K₂O, the balance beingimpurities, a fiber diameter of 3 to 4 μm and a fiber length of 3 to 10mm, is mixed with 100 ml of a 5M solution of formic acid. For the mixinga high-shear mixer should be used to ensure effective mixing and tospeed up the dissolution process. The dissolution is usually complete in1 to 2 hours. When the fibres are completely dissolved a small amount ofpolymer, such as polyethylene glycol with a molar mass of 1000 to 10000,is added, appr. 1% by weight based on the total solids content of thesolution. During the addition of the polymer, the solution is constantlymixed to stabilize the formed particles. By altering the amount ofpolymer and the time of addition, i.e. the point of time when all fibreshave dissolved, the size of the sol particles can be changed to obtainoptimal gelling and binding properties. The colloidal particle sol isthen kept under continuous mixing to ensure that the polymer adsorbs tothe surface of the particles.

[0043] When used as a binder for making mineral wool products,.thebinder so prepared can be applied by spraying onto mineral fibres in aconventional manner. The binder is cured and excess water is driven awayby raising the temperature up to about 150° C.

[0044] The said binder can also be used as a binder in a briquette bymixing the binder with finely ground mineral raw material in a mixer,for example of Henschel type. It can be advantageous to add a smallamount of water for forming the mixture in moulds. Curing is obtained byraising the temperature, but also air drying is possible.

EXAMPLE 2

[0045] 2.1 g of fibres having a composition corresponding to that ofExample 1, were dissolved in 100 ml of 1 M formic acid. Afterdissolution of the fibres, the solution was centrifuged to remove theimpurities. The sample was then studied using light-scatteringmeasurements. Nucleation of primary particles took place in the solutionand the particles showed a steady growth, that is an increase in sizewith time, as is evident from the appended FIG. 1.

[0046] If the dispersion is not stabilized, it will gel over time as isevident from the appended FIG. 2, which illustrates tests carried out bydissolving 1.15 g of fibres having the composition given above, in 100ml of formic acid of different concentrations. As can be seen from theFIG. 2, the gelling time varied between 5 and 12 days.

[0047] In order to study the pH behaviour as a function of time, 1.15 gof fibres having the composition given above, were dissolved in 100 mlof acetic acid of varying concentration, as indicated in the FIG. 3.Equilibrium pH was reached within a couple of hours indicating that thefiber material had dissolved. Lower concentrations of acid resulted in ahigher pH, indicating that there was less acid remaining in thesolution. At higher concentration of acid, more acid remained after thefibres had dissolved, thus keeping the pH at a lower level.

[0048] A similar test was carried out by dissolving 1.15 g of fibres(diameter 3-4 μm and length appr. 3-10 mm) having the composition givenabove, in 100 ml of formic acid with varying concentration. At lowconcentration, the required dissolution time was appr. 15 to 20 hours.When the concentration was increased, the dissolution time decreased to1 to 2 hours.

1. A colloidal silicate dispersion containing silica and alumina in anaqueous medium, wherein the molar ratio between silica and alumina is inthe range of 2-12.
 2. The dispersion according to claim 1, wherein themolar ratio between silica and alumina is in the range of 2.5-8.
 3. Thedispersion according to claim 1, wherein the molar ratio between silicaand alumina is in the range of 3.5-6.
 4. The dispersion according to anyone of the claims 1 to 3 containing alkali oxide or alkali oxides,wherein the molar ratio between silica and the sum of alkali oxides isin the range of 10-350.
 5. The dispersion according to claim 4, whereinthe molar ratio between silica and the sum of alkali oxides is in therange of 15-150.
 6. The dispersion according to any one of the precedingclaims containing calcium and/or magnesium oxide and/or iron oxide,wherein the molar ratio between silica and the sum of calcium oxide,magnesium oxide and iron oxide (as FeO) is in the range of 0.5-2,preferably 0.6-1.5.
 7. The dispersion according to any one of thepreceding claims wherein the particle size is 1 to 1000 nm, preferably10 to 100 nm.
 8. The dispersion according to any one of the precedingclaims having a dry matter content of 5 to 60% by weight.
 9. A gelformed through gel formation, including coagulation, of the dispersionaccording to any one of the preceding claims.
 10. Method for thepreparation of a colloidal silicate dispersion containing silica andalumina, comprising dissolving a particulate mineral material containingsilica and alumina in a molar ratio in the range of 2-12 in an aqueoussolution, to form a solution containing nucleated re-precipitatedparticles from the material, stabilizing the so obtained solution toform a dispersion, and optionally adjusting the dry matter content ofthe dispersion.
 11. The method according to claim 10, wherein theparticulate mineral material has a glassy amorphous structure.
 12. Themethod according to claim 10 or 11, wherein the particulate mineralmaterial contains alkali oxide or alkali oxides and the molar ratio ofsilica to the sum of the alkali oxides is in the range of 10-350,preferably 15-150.
 13. The method according to any one of the claims 10to 12, wherein the particulate mineral material contains calcium and/ormagnesium oxide and/or iron oxide, wherein the molar ratio betweensilica and the sum of calcium oxide, magnesium oxide and iron oxide (asFeO) is in the range of 0.5-2, preferably 0.6-1.5.
 14. The methodaccording to any one of the claims 10 to 13, wherein the particulatemineral material contains 35-45% by weight SiO₂ and 8-25% by weightAl₂O₃.
 15. The method according to any one of the claims 10 to 14,wherein the particulate mineral material contains, calculated as % byweight, SiO₂ 35-45 Al₂O₃ 10-25 R₂O 0.2-3, 

wherein R means Na or K.
 16. The method according to claim 15, whereinthe particulate mineral material contains, calculated as % by weight CaO12-35 MgO  6-20 FeO  2-10


17. The method according to any one of the claims 10 to 14, wherein theparticulate mineral material contains, calculated as % by weight, SiO₂35-45 Al₂O₃  8-13 R₂O 0.2-1, 

wherein R means Na or K.
 18. The method according to claim 17, whereinthe particulate mineral material contains, calculated as % by weight,CaO 30-40 MgO  5-11 FeO (total iron) 0.1-1. 


19. The method according to any one of the claims 10 to 18, wherein theparticulate mineral material is a mineral fibre product, a waste productfrom mineral fibre production, such as spinning waste, unused fibres orproducts, as well as post-consumer mineral fibre products.
 20. Themethod according to any one of the claims 10 to 19, wherein the solutionis stabilized by means of a pH change or by changing the electrolyticcharacter of the solution.
 21. The method according to any one of theclaims 10 to 20, wherein the solution is stabilized by means ofsurfactants and/or polymers.
 22. The method according to any one of theclaims 10 to 21, wherein the aqueous solution is a solution of aninorganic or organic acid, preferably an aqueous solution containing anacid selected from HCl, HNO₃, H₂SO₄, H₃PO₄, or an organic acid, such asformic, acetic and propionic acid.
 23. The method according to claim 22,wherein the acid is formic, acetic or propionic acid.
 24. The methodaccording to any of the claims 10 to 21, wherein the aqueous solution isan alkaline solution.
 25. The method according to claim 24, wherein thealkaline solution is an alkali or ammonium, or an alkaline earth metalhydroxide, carbonate or hydrocarbonate solution, preferably selectedfrom the group consisting of a sodium, potassium, lithium or ammonium,or calcium or magnesium hydroxide solution.
 26. The method according toany one of the claims 10 to 25, wherein the dispersion is adjusted to adry matter content of 5 to 60% by weight.
 27. The method according toany one of the claims 10 to 26, wherein the dissolution takes place at atemperature of 80 to 100° C., preferably while stirring.
 28. The methodaccording to any one of the claims 10 to 27, comprising the additionalstep of forming a gel from the dispersion.
 29. The method according toclaim 28, wherein gel formation is brought about by affecting a pHchange and/or by the addition of a salt, and/or by removing water fromthe dispersion.
 30. Use of a dispersion according to any one of theclaims 1 to 9, or of a product made by a method according to any one ofthe claims 10 to 29, as a binding agent, such as in a bindingcomposition, a coating substance or an adhesive.
 31. The use accordingto claim 30 as a binder in mineral wool production, or for raw materialbriquettes for mineral wool production.
 32. The use according to claim30 as a coating layer material, or as a component of such a material,for mineral wool products.
 33. The use according to claim 30 as anadhesive in mineral wool laminates, or in construction panels comprisinga mineral wool layer laminated to a metal sheet for binding such a layerto the metal sheet.